coap.py

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#   Copyright 2012-2013 Eric Ptak - trouch.com
#
#   Licensed under the Apache License, Version 2.0 (the "License");
#   you may not use this file except in compliance with the License.
#   You may obtain a copy of the License at
#
#       http://www.apache.org/licenses/LICENSE-2.0
#
#   Unless required by applicable law or agreed to in writing, software
#   distributed under the License is distributed on an "AS IS" BASIS,
#   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
#   See the License for the specific language governing permissions and
#   limitations under the License.

from webiopi.utils.version import PYTHON_MAJOR
from webiopi.utils.logger import info, exception 

import socket
import struct
import logging
import threading

M_PLAIN = "text/plain"
M_JSON  = "application/json"

if PYTHON_MAJOR >= 3:
    from urllib.parse import urlparse
else:
    from urlparse import urlparse

try :
    import _webiopi.GPIO as GPIO
except:
    pass

def HTTPCode2CoAPCode(code):
    return int(code/100) * 32 + (code%100)

   
class COAPContentFormat():
    FORMATS = {0: "text/plain",
               40: "application/link-format",
               41: "application/xml",
               42: "application/octet-stream",
               47: "application/exi",
               50: "application/json"
               }

    @staticmethod
    def getCode(fmt):
        if fmt == None:
            return None
        for code in COAPContentFormat.FORMATS:
            if COAPContentFormat.FORMATS[code] == fmt:
                return code
        return None
    
    @staticmethod
    def toString(code):
        if code == None:
            return None

        if code in COAPContentFormat.FORMATS:
            return COAPContentFormat.FORMATS[code]
        
        raise Exception("Unknown content format %d" % code)
        

class COAPOption():
    OPTIONS = {1: "If-Match",
               3: "Uri-Host",
               4: "ETag",
               5: "If-None-Match",
               7: "Uri-Port",
               8: "Location-Path",
               11: "Uri-Path",
               12: "Content-Format",
               14: "Max-Age",
               15: "Uri-Query",
               16: "Accept",
               20: "Location-Query",
               35: "Proxy-Uri",
               39: "Proxy-Scheme"
               }
    
    IF_MATCH = 1
    URI_HOST = 3
    ETAG = 4
    IF_NONE_MATCH = 5
    URI_PORT = 7
    LOCATION_PATH = 8
    URI_PATH = 11
    CONTENT_FORMAT = 12
    MAX_AGE = 14
    URI_QUERY = 15
    ACCEPT = 16
    LOCATION_QUERY = 20
    PROXY_URI = 35
    PROXY_SCHEME = 39
    
    
class COAPMessage():
    TYPES = ["CON", "NON", "ACK", "RST"]
    CON = 0
    NON = 1
    ACK = 2
    RST = 3

    def __init__(self, msg_type=0, code=0, uri=None):
        self.version = 1
        self.type    = msg_type
        self.code    = code
        self.id      = 0
        self.token   = None
        self.options = []
        self.host    = ""
        self.port    = 5683
        self.uri_path = ""
        self.content_format = None
        self.payload = None
        
        if uri != None:
            p = urlparse(uri)
            self.host = p.hostname
            if p.port:
                self.port = int(p.port)
            self.uri_path = p.path
        
    def __getOptionHeader__(self, byte):
        delta  = (byte & 0xF0) >> 4
        length = byte & 0x0F
        return (delta, length)  
        
    def __str__(self):
        result = []
        result.append("Version: %s" % self.version)
        result.append("Type: %s" % self.TYPES[self.type])
        result.append("Code: %s" % self.CODES[self.code])
        result.append("Id: %s" % self.id)
        result.append("Token: %s" % self.token)
        #result.append("Options: %s" % len(self.options))
        #for option in self.options:
        #    result.append("+ %d: %s" % (option["number"], option["value"]))
        result.append("Uri-Path: %s" % self.uri_path)
        result.append("Content-Format: %s" % (COAPContentFormat.toString(self.content_format) if self.content_format else M_PLAIN))
        result.append("Payload: %s" % self.payload)
        result.append("")
        return '\n'.join(result)
        
    def getOptionHeaderValue(self, value):
        if value > 268:
            return 14
        if value > 12:
            return 13
        return value
    
    def getOptionHeaderExtension(self, value):
        buff = bytearray()
        v = self.getOptionHeaderValue(value)
        
        if v == 14:
            value -= 269
            buff.append((value & 0xFF00) >> 8)
            buff.append(value & 0x00FF)

        elif v == 13:
            value -= 13
            buff.append(value)

        return buff
    
    def appendOption(self, buff, lastnumber, option, data):
        delta = option - lastnumber
        length = len(data)
        
        d = self.getOptionHeaderValue(delta)
        l = self.getOptionHeaderValue(length)
        
        b  = 0
        b |= (d << 4) & 0xF0  
        b |= l & 0x0F
        buff.append(b)
        
        ext = self.getOptionHeaderExtension(delta);
        for b in ext:
            buff.append(b)

        ext = self.getOptionHeaderExtension(length);
        for b in ext:
            buff.append(b)

        for b in data:
            buff.append(b)

        return option

    def getBytes(self):
        buff = bytearray()
        byte  = (self.version & 0x03) << 6
        byte |= (self.type & 0x03) << 4
        if self.token:
            token_len = min(len(self.token), 8);
        else:
            token_len = 0
        byte |= token_len
        buff.append(byte)
        buff.append(self.code)
        buff.append((self.id & 0xFF00) >> 8)
        buff.append(self.id & 0x00FF)
        
        if self.token:
            for c in self.token:
                buff.append(c)

        lastnumber = 0
        
        if len(self.uri_path) > 0:
            paths = self.uri_path.split("/")
            for p in paths:
                if len(p) > 0:
                    if PYTHON_MAJOR >= 3:
                        data = p.encode()
                    else:
                        data = bytearray(p)
                    lastnumber = self.appendOption(buff, lastnumber, COAPOption.URI_PATH, data)

        if self.content_format != None:
            data = bytearray()
            fmt_code = self.content_format
            if fmt_code > 0xFF:
                data.append((fmt_code & 0xFF00) >> 8)
            data.append(fmt_code & 0x00FF)
            lastnumber = self.appendOption(buff, lastnumber, COAPOption.CONTENT_FORMAT, data)
            
        buff.append(0xFF)
        
        if self.payload:
            if PYTHON_MAJOR >= 3:
                data = self.payload.encode()
            else:
                data = bytearray(self.payload)
            for c in data:
                buff.append(c)
        
        return buff
    
    def parseByteArray(self, buff):
        self.version = (buff[0] & 0xC0) >> 6
        self.type    = (buff[0] & 0x30) >> 4
        token_length = buff[0] & 0x0F
        index = 4
        if token_length > 0:
            self.token = buff[index:index+token_length]

        index += token_length
        self.code    = buff[1]
        self.id      = (buff[2] << 8) | buff[3]
        
        number = 0

        # process options
        while index < len(buff) and buff[index] != 0xFF:
            (delta, length) = self.__getOptionHeader__(buff[index])
            offset = 1

            # delta extended with 1 byte
            if delta == 13:
                delta += buff[index+offset]
                offset += 1
            # delta extended with 2 buff
            elif delta == 14:
                delta += 255 + ((buff[index+offset] << 8) | buff[index+offset+1])
                offset += 2
            
            # length extended with 1 byte
            if length == 13:
                length += buff[index+offset]
                offset += 1
                
            # length extended with 2 buff
            elif length == 14:
                length += 255 + ((buff[index+offset] << 8) | buff[index+offset+1])
                offset += 2

            number += delta
            valueBytes = buff[index+offset:index+offset+length]
            # opaque option value
            if number in [COAPOption.IF_MATCH, COAPOption.ETAG]:
                value = valueBytes
            # integer option value
            elif number in [COAPOption.URI_PORT, COAPOption.CONTENT_FORMAT, COAPOption.MAX_AGE, COAPOption.ACCEPT]:
                value = 0
                for b in valueBytes:
                    value <<= 8
                    value |= b
            # string option value
            else:
                if PYTHON_MAJOR >= 3:
                    value = valueBytes.decode()
                else:
                    value = str(valueBytes)
            self.options.append({'number': number, 'value': value})
            index += offset + length

        index += 1 # skip 0xFF / end-of-options
        
        if len(buff) > index:
            self.payload = buff[index:]
        else:
            self.payload = ""
        
        for option in self.options:
            (number, value) = option.values()
            if number == COAPOption.URI_PATH:
                self.uri_path += "/%s" % value


class COAPRequest(COAPMessage):
    CODES = {0: None,
             1: "GET",
             2: "POST",
             3: "PUT",
             4: "DELETE"
             }

    GET    = 1
    POST   = 2
    PUT    = 3
    DELETE = 4

    def __init__(self, msg_type=0, code=0, uri=None):
        COAPMessage.__init__(self, msg_type, code, uri)

class COAPGet(COAPRequest):
    def __init__(self, uri):
        COAPRequest.__init__(self, COAPMessage.CON, COAPRequest.GET, uri)

class COAPPost(COAPRequest):
    def __init__(self, uri):
        COAPRequest.__init__(self, COAPMessage.CON, COAPRequest.POST, uri)

class COAPPut(COAPRequest):
    def __init__(self, uri):
        COAPRequest.__init__(self, COAPMessage.CON, COAPRequest.PUT, uri)

class COAPDelete(COAPRequest):
    def __init__(self, uri):
        COAPRequest.__init__(self, COAPMessage.CON, COAPRequest.DELETE, uri)

class COAPResponse(COAPMessage):    
    CODES = {0: None,
             64: "2.00 OK",
             65: "2.01 Created",
             66: "2.02 Deleted",
             67: "2.03 Valid",
             68: "2.04 Changed",
             69: "2.05 Content",
             128: "4.00 Bad Request",
             129: "4.01 Unauthorized",
             130: "4.02 Bad Option",
             131: "4.03 Forbidden",
             132: "4.04 Not Found",
             133: "4.05 Method Not Allowed",
             134: "4.06 Not Acceptable",
             140: "4.12 Precondition Failed",
             141: "4.13 Request Entity Too Large",
             143: "4.15 Unsupported Content-Format",
             160: "5.00 Internal Server Error",
             161: "5.01 Not Implemented",
             162: "5.02 Bad Gateway",
             163: "5.03 Service Unavailable",
             164: "5.04 Gateway Timeout",
             165: "5.05 Proxying Not Supported"            
            }

    # 2.XX
    OK      = 64
    CREATED = 65
    DELETED = 66
    VALID   = 67
    CHANGED = 68
    CONTENT = 69
    
    # 4.XX
    BAD_REQUEST         = 128
    UNAUTHORIZED        = 129
    BAD_OPTION          = 130
    FORBIDDEN           = 131
    NOT_FOUND           = 132
    NOT_ALLOWED         = 133
    NOT_ACCEPTABLE      = 134
    PRECONDITION_FAILED = 140
    ENTITY_TOO_LARGE    = 141
    UNSUPPORTED_CONTENT = 143
    
    # 5.XX
    INTERNAL_ERROR          = 160
    NOT_IMPLEMENTED         = 161
    BAD_GATEWAY             = 162
    SERVICE_UNAVAILABLE     = 163
    GATEWAY_TIMEOUT         = 164
    PROXYING_NOT_SUPPORTED  = 165
    
    def __init__(self):
        COAPMessage.__init__(self)

class COAPClient():
    def __init__(self):
        self.socket = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
        self.socket.settimeout(1.0)
        self.socket.setsockopt(socket.IPPROTO_IP, socket.IP_MULTICAST_TTL, 2)
        
    def sendRequest(self, message):
        data = message.getBytes();
        sent = 0
        while sent<4:
            try:
                self.socket.sendto(data, (message.host, message.port))
                data = self.socket.recv(1500)
                response = COAPResponse()
                response.parseByteArray(bytearray(data))
                return response
            except socket.timeout:
                sent+=1
        return None

class COAPServer(threading.Thread):
    logger = logging.getLogger("CoAP")

    def __init__(self, host, port, handler):
        threading.Thread.__init__(self, name="COAPThread")
        self.handler = COAPHandler(handler)
        self.host = host
        self.port = port
        self.multicast_ip = '224.0.1.123'
        if socket.has_ipv6:
            address_family = socket.AF_INET6
        else:
            address_family = socket.AF_INET
        try:
            self.socket = socket.socket(address_family, socket.SOCK_DGRAM)
        except:
            self.socket = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
        self.socket.bind(('', port))
        self.socket.settimeout(1)
        self.running = True
        self.start()
        
    def run(self):
        info("CoAP Server binded on coap://%s:%s/" % (self.host, self.port))
        while self.running == True:
            try:
                (request, client) = self.socket.recvfrom(1500)
                requestBytes = bytearray(request)
                coapRequest = COAPRequest()
                coapRequest.parseByteArray(requestBytes)
                coapResponse = COAPResponse()
                #self.logger.debug("Received Request:\n%s" % coapRequest)
                self.processMessage(coapRequest, coapResponse)
                #self.logger.debug("Sending Response:\n%s" % coapResponse)
                responseBytes = coapResponse.getBytes()
                self.socket.sendto(responseBytes, client)
                self.logger.debug('"%s %s CoAP/%.1f" - %s (Client: %s)' % (coapRequest.CODES[coapRequest.code], coapRequest.uri_path, coapRequest.version, coapResponse.CODES[coapResponse.code], client[0]))
                
            except socket.timeout as e:
                continue
            except Exception as e:
                if self.running == True:
                    exception(e)
            
        info("CoAP Server stopped")
    
    def enableMulticast(self):
        while not self.running:
            pass
        mreq = struct.pack("4sl", socket.inet_aton(self.multicast_ip), socket.INADDR_ANY)
        self.socket.setsockopt(socket.IPPROTO_IP, socket.IP_ADD_MEMBERSHIP, mreq)
        info("CoAP Server binded on coap://%s:%s/ (MULTICAST)" % (self.multicast_ip, self.port))
                
    def stop(self):
        self.running = False
        self.socket.close()
        
    def processMessage(self, request, response):
        if request.type == COAPMessage.CON:
            response.type = COAPMessage.ACK
        else:
            response.type = COAPMessage.NON

        if request.token:
            response.token = request.token

        response.id = request.id
        response.uri_path = request.uri_path
        
        if request.code == COAPRequest.GET:
            self.handler.do_GET(request, response)
        elif request.code == COAPRequest.POST:
            self.handler.do_POST(request, response)
        elif request.code / 32 == 0:
            response.code = COAPResponse.NOT_IMPLEMENTED
        else:
            exception(Exception("Received CoAP Response : %s" % response))
        
class COAPHandler():
    def __init__(self, handler):
        self.handler = handler
    
    def do_GET(self, request, response):
        try:
            (code, body, contentType) = self.handler.do_GET(request.uri_path[1:], True)
            if code == 0:
                response.code = COAPResponse.NOT_FOUND
            elif code == 200:
                response.code = COAPResponse.CONTENT
            else:
                response.code =  HTTPCode2CoAPCode(code)
            response.payload = body
            response.content_format = COAPContentFormat.getCode(contentType)
        except (GPIO.InvalidDirectionException, GPIO.InvalidChannelException, GPIO.SetupException) as e:
            response.code = COAPResponse.FORBIDDEN
            response.payload = "%s" % e
        except Exception as e:
            response.code = COAPResponse.INTERNAL_ERROR
            raise e
        
    def do_POST(self, request, response):
        try:
            (code, body, contentType) = self.handler.do_POST(request.uri_path[1:], request.payload, True)
            if code == 0:
                response.code = COAPResponse.NOT_FOUND
            elif code == 200:
                response.code = COAPResponse.CHANGED
            else:
                response.code =  HTTPCode2CoAPCode(code)
            response.payload = body
            response.content_format = COAPContentFormat.getCode(contentType)
        except (GPIO.InvalidDirectionException, GPIO.InvalidChannelException, GPIO.SetupException) as e:
            response.code = COAPResponse.FORBIDDEN
            response.payload = "%s" % e
        except Exception as e:
            response.code = COAPResponse.INTERNAL_ERROR
            raise e